1. Field of the Invention
The present invention relates to a manufacturing method for a touch control circuit, and more specifically, to a method for manufacturing conducting films of a touch control circuit on two opposite surfaces of a transparent substrate by sputtering, exposure, developing, and etching methods.
2. Description of the Related Art
Conventional touch panels are generally divided into resistive touch panels and capacitive touch panels. The resistive touch panels are used by figure, pen or other medium pressing the surface thereof to generate touch control signals. The capacitive touch panels are used by the figure touching the surface thereof to generate the touch control signals. Thus, the capacitive touch panels are more sensitive than the resistive touch panels. Therefore, the touch panels of current advanced electronic devices, such as mobile phone, global positioning system (GPS), personal digital assistant (PDA), palm-sized PC, or information appliance, etc., are mostly the capacitive touch panels. The capacitive touch panels have a touch control circuit arranged therein, which is manufactured by using sputtering, exposure, developing, and etching methods to stack transparent conducting indium tin oxide (ITO) in series on two opposite surfaces of a glass substrate. The touch control circuit includes an upper conducting film formed on a top surface of the transparent substrate, and a lower conducting film formed on a bottom surface of the transparent substrate. Thus, a capacitive effect is produced between the upper, lower conducting films and the body of people, to generate an induced current, which can be used to calculate the coordinate value of a touch control position.
Furthermore, the typical manufacturing method for the above touch control circuit includes vacuum sputtering an upper conducting material and a lower conducting material on top and bottom surfaces of a glass substrate respectively; contacting an upper photoresist layer on the upper conducting material, and contacting a protective layer on the lower conducting material; shielding the photoresist layer with a mask having empty circuit patterns, and exposing the upper photoresist layer by ultra-violet (UV) light through the mask having the empty circuit patterns; developing the upper photoresist layer by a developer to expose a region of the upper conducting material, which should be etched; etching the exposed upper conducting material in an etchant to form an upper conducting film, and removing the residual photoresist layer on the upper conducting film and the protective layer on the lower conducting material; next, contacting a lower photoresist layer on the lower conducting material and contacting another protective layer on the upper conducting film; shielding the lower photoresist layer on the lower conducting material with another mask having empty circuit patterns, using the upper conducting film as an aligning benchmark for the lower photoresist layer, aligning the mask by images of the upper conducting film obtained by an image pick-up device, such as CCD, exposing the lower photoresist layer by the UV light through the mask having the empty circuit patterns; developing the lower photoresist layer by a developer to expose an etching region of the lower conducting material, which should be etched; etching the exposed region of the lower conducting material in the etchant, to form a lower conducting film, and removing the residual photoresist layer on the lower conducting film and the protective layer on the upper conducting film.
However, the typical manufacturing method for the touch control circuit must repeat the steps of contacting and removing the photoresist layer, and/or the protective layer, and repeat the developing and/or etching processes. Thus, the typical manufacturing method consumes more manufacturing time and cost.
What is needed, is providing a manufacturing method for a touch control circuit, which can solve the above problems.